USB to RS232 converter problem (prolific chip)

[Andrei Kolu]

On Sunday 06 April 2008 00:24:38 Andrei Kolu wrote:
> On Saturday 05 April 2008 23:48:59 you wrote:
> > On Sat, 5 Apr 2008, Andrei Kolu wrote:
> > > I have problems using USB to RS232  converter under FreeBSD 6.3-STABLE
> > > when connecting to any Cisco gear over serial link. I connect my
> > > adapter to notebook and dmesg output looks like this one:
> > >
> > > ucom0: Prolific Technology Inc. USB-Serial Controller D, rev 1.10/4.00,
> > > addr 2
> > >
> > > I have also following modules loaded:
> > >
> > > 8    1 0xc0c17000 3540     umodem.ko# cu -l /dev/ttyU0
> > > Connected
> > >
> > > 9    4 0xc0c1b000 3208     ucom.ko
> > > 10    1 0xc0c1f000 2f54     uplcom.ko
> > > 13    1 0xc0c2f000 3384     ubsa.ko
> > >
> > > Now I try to connect to Cisco box:
> > >
> > > # cu -l /dev/ttyU0
> > > Connected
> >
> > Use /dev/cuaU0 instead.
> >
> > -Warren Block * Rapid City, South Dakota USA
>
> There is no difference if I connect through /dev/ttyU0 or /dev/cuaU0 and
> even through ttyU1 or cuaU1 (when second serial converter is connected)-
> same problem. I tried on other computer with FreeBSD 6.1 and 7.0-STABLE
> snapshot from march- same results.
>
> Something is broken on FreeBSD side- strange thing is that when I turn
> power down on cisco box and turn in on again then I see scrolling text from
> cisco gear but there is no feedback to keyboard activity. How to debug this
> issue?
>
Some progress on debugging! Just kiddin...

I removed converter from USB and FreeBSD 7.0 kernel dumped following 
information:

ucom0: ucomreadcb: IOERROR
ucom0: at uhub1 port 1 (addr 2) disconnected
ucom0: uplcom_set_line_status: STALLED


Fatal trap 12: page fault while in kernel mode
cpuid = 1; apic id = 01
fault virtual address 	= 0xb0
fault code 			= supervisor read data, page not present
instruction pointer 		= 0x8:0xffffffff80446f72
stack pointer 			= 0x10:0xffffffffae796a00
frame pointer 			= 0x10:0xffffff000172b400
code segment 		= base 0x0, limit 0xfffff, type 0x1b
					= DPL 0, pres 1, long 1, def32 0, gran 1
processor eflags		= interrupt enabled, resume, IOPL = 0
current process		= 876 (cu)
trap number			= 12
panic: page fault
cpuid: 1
Uptime: 8m41s
Physical memory: 2802 MB
Dumping 126 MB: 111 95 79 63 47 31 15
Dump complete